6. A thin oil film on a water surface appears coloured because of A.Reflection B.Interference C.Diffraction D.Polarization
Option B Solution: A thin oil film on a water surface appears coloured because of thin-film interference which involves the interference of light waves reflecting off the top surface of a film with the waves reflecting from the bottom surface. The refractive index of oil is larger than that of water, therefore the reflection on the back side occurs.
